node-gettext

node-gettext

node-gettext is a JavaScript implementation of (a large subset of) gettext, a localization framework originally written in C.

If you just want to parse or compile mo/po files, for use with this library or elsewhere, check out gettext-parser.

NOTE: This is the README for v2 of node-gettext, which introduces several braking changes. You can find the README for v1 here.

• Features
  • Differences from GNU gettext
• Installation
• Usage
  • Error events
  • Recipes
• API
• Migrating from v1 to v2
• License
• See also

Features

• Supports domains, contexts and plurals
• Supports .json, .mo and .po files with the help of gettext-parser
• Ships with plural forms for 136 languages
• Change locale or domain on the fly
• Useful error messages enabled by a debug option
• Emits events for internal errors, such as missing translations

Differences from GNU gettext

There are two main differences between node-gettext and GNU's gettext:

1. There are no categories. GNU gettext features categories such as LC_MESSAGES, LC_NUMERIC and LC_MONETARY, but since there already is a plethora of great JavaScript libraries to deal with numbers, currencies, dates etc, node-gettext is simply targeted towards strings/phrases. You could say it just assumes the LC_MESSAGES category at all times.
2. You have to read translation files from the file system yourself. GNU gettext is a C library that reads files from the file system. This is done using bindtextdomain(domain, localesDirPath) and setlocale(category, locale), where these four parameters combined are used to read the appropriate translations file.

However, since node-gettext needs to work both on the server in web browsers (which usually is referred to as it being universal or isomorphic JavaScript), it is up to the developer to read translation files from disk or somehow provide it with translations as pure JavaScript objects using addTranslations(locale, domain, translations).

bindtextdomain will be provided as an optional feature in a future release.

Installation

npm install --save node-gettext

Usage

import Gettext from 'node-gettext'
import swedishTranslations from './translations/sv-SE.json'

const gt = new Gettext()
gt.addTranslations('sv-SE', 'messages', swedishTranslations)
gt.setLocale('sv-SE')

gt.gettext('The world is a funny place')
// -> "Världen är en underlig plats"

Error events

// Add translations etc...

gt.on('error', error => console.log('oh nose', error))
gt.gettext('An unrecognized message')
// -> 'oh nose', 'An unrecognized message'

Recipes

Load and add translations from .mo or .po files

node-gettext expects all translations to be in the format specified by gettext-parser. Therefor, you should use that to parse .mo or .po files.

Here is an example where we read a bunch of translation files from disk and add them to our Gettext instance:

import fs from 'fs'
import path from 'path'
import Gettext from 'node-gettext'
import { po } from 'gettext-parser'

// In this example, our translations are found at
// path/to/locales/LOCALE/DOMAIN.po
const translationsDir = 'path/to/locales'
const locales = ['en', 'fi-FI', 'sv-SE']
const domain = 'messages'

const gt = new Gettext()

locales.forEach((locale) => {
    const fileName = `${domain}.po`
    const translationsFilePath = path.join(translationsDir, locale, fileName)
    const translationsContent = fs.readFileSync(translationsFilePath)

    const parsedTranslations = po.parse(translationsContent)
    gt.addTranslations(locale, domain, parsedTranslations)
})

API

Gettext

• Gettext
  • new Gettext([options])
  • .on(eventName, callback)
  • .off(eventName, callback)
  • .addTranslations(locale, domain, translations)
  • .setLocale(locale)
  • .setTextDomain(domain)
  • .gettext(msgid) ⇒ String
  • .dgettext(domain, msgid) ⇒ String
  • .ngettext(msgid, msgidPlural, count) ⇒ String
  • .dngettext(domain, msgid, msgidPlural, count) ⇒ String
  • .pgettext(msgctxt, msgid) ⇒ String
  • .dpgettext(domain, msgctxt, msgid) ⇒ String
  • .npgettext(msgctxt, msgid, msgidPlural, count) ⇒ String
  • .dnpgettext(domain, msgctxt, msgid, msgidPlural, count) ⇒ String
  • .textdomain()
  • .setlocale()
  • .addTextdomain()

new Gettext([options])

Creates and returns a new Gettext instance.

Returns: Object - A Gettext instance Params

• [options]: Object - A set of options
  • .sourceLocale: String - The locale that the source code and its texts are written in. Translations for this locale is not necessary.
  • .debug: Boolean - Whether to output debug info into the console.

gettext.on(eventName, callback)

Adds an event listener.

Params

• eventName: String - An event name
• callback: function - An event handler function

gettext.off(eventName, callback)

Removes an event listener.

Params

• eventName: String - An event name
• callback: function - A previously registered event handler function

gettext.addTranslations(locale, domain, translations)

Stores a set of translations in the set of gettext catalogs.

Params

• locale: String - A locale string
• domain: String - A domain name
• translations: Object - An object of gettext-parser JSON shape

Example

gt.addTranslations('sv-SE', 'messages', translationsObject)

gettext.setLocale(locale)

Sets the locale to get translated messages for.

Params

• locale: String - A locale

Example

gt.setLocale('sv-SE')

gettext.setTextDomain(domain)

Sets the default gettext domain.

Params

• domain: String - A gettext domain name

Example

gt.setTextDomain('domainname')

gettext.gettext(msgid) ⇒ String

Translates a string using the default textdomain

Returns: String - Translation or the original string if no translation was found
Params

• msgid: String - String to be translated

Example

gt.gettext('Some text')

gettext.dgettext(domain, msgid) ⇒ String

Translates a string using a specific domain

Returns: String - Translation or the original string if no translation was found
Params

• domain: String - A gettext domain name
• msgid: String - String to be translated

Example

gt.dgettext('domainname', 'Some text')

gettext.ngettext(msgid, msgidPlural, count) ⇒ String

Translates a plural string using the default textdomain

Returns: String - Translation or the original string if no translation was found
Params

• msgid: String - String to be translated when count is not plural
• msgidPlural: String - String to be translated when count is plural
• count: Number - Number count for the plural

Example

gt.ngettext('One thing', 'Many things', numberOfThings)

gettext.dngettext(domain, msgid, msgidPlural, count) ⇒ String

Translates a plural string using a specific textdomain

Returns: String - Translation or the original string if no translation was found
Params

• domain: String - A gettext domain name
• msgid: String - String to be translated when count is not plural
• msgidPlural: String - String to be translated when count is plural
• count: Number - Number count for the plural

Example

gt.dngettext('domainname', 'One thing', 'Many things', numberOfThings)

gettext.pgettext(msgctxt, msgid) ⇒ String

Translates a string from a specific context using the default textdomain

Returns: String - Translation or the original string if no translation was found
Params

• msgctxt: String - Translation context
• msgid: String - String to be translated

Example

gt.pgettext('sports', 'Back')

gettext.dpgettext(domain, msgctxt, msgid) ⇒ String

Translates a string from a specific context using s specific textdomain

Returns: String - Translation or the original string if no translation was found
Params

• domain: String - A gettext domain name
• msgctxt: String - Translation context
• msgid: String - String to be translated

Example

gt.dpgettext('domainname', 'sports', 'Back')

gettext.npgettext(msgctxt, msgid, msgidPlural, count) ⇒ String

Translates a plural string from a specific context using the default textdomain

Returns: String - Translation or the original string if no translation was found
Params

• msgctxt: String - Translation context
• msgid: String - String to be translated when count is not plural
• msgidPlural: String - String to be translated when count is plural
• count: Number - Number count for the plural

Example

gt.npgettext('sports', 'Back', '%d backs', numberOfBacks)

gettext.dnpgettext(domain, msgctxt, msgid, msgidPlural, count) ⇒ String

Translates a plural string from a specifi context using a specific textdomain

Returns: String - Translation or the original string if no translation was found
Params

• domain: String - A gettext domain name
• msgctxt: String - Translation context
• msgid: String - String to be translated
• msgidPlural: String - If no translation was found, return this on count!=1
• count: Number - Number count for the plural

Example

gt.dnpgettext('domainname', 'sports', 'Back', '%d backs', numberOfBacks)

gettext.textdomain()

C-style alias for setTextDomain

See: Gettext#setTextDomain

gettext.setlocale()

C-style alias for setLocale

See: Gettext#setLocale

gettext.addTextdomain()

Deprecated

This function will be removed in the final 2.0.0 release.

Migrating from v1 to v2

Version 1 of node-gettext confused domains with locales, which version 2 has corrected. node-gettext also no longer parses files or file paths for you, but accepts only ready-parsed JSON translation objects.

Here is a full list of all breaking changes:

• textdomain(domain) is now setLocale(locale)
• dgettext, dngettext, dpgettext and dnpgettext does not treat the leading domain argument as a locale, but as a domain. To get a translation from a certain locale you need to call setLocale(locale) beforehand.
• A new setTextDomain(domain) has been introduced
• addTextdomain(domain, file) is now addTranslations(locale, domain, translations)
• addTranslations(locale, domain, translations) only accepts a JSON object with the shape described in the gettext-parser README. To load translations from .mo or .po files, use gettext-parser, and it will provide you with valid JSON objects.
• _currentDomain is now domain
• domains is now catalogs
• The instance method __normalizeDomain(domain) has been replaced by a static method Gettext.getLanguageCode(locale)

License

MIT

See also

• gettext-parser - Parsing and compiling gettext translations between .po/.mo files and JSON
• lioness – Gettext library for React
• react-gettext-parser - Extracting gettext translatable strings from JS(X) code
• narp - Workflow CLI tool that syncs translations between your app and Transifex